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Flashcards in Immuno 4 Deck (38):
1

all antibodies are of a class of protein called

immunoglobulin

2

structure of an immunoglobulin

4 polypeptide chains bound together by disulfide bonds
(2 light chains, 2 heavy chains)

3

what are the 2 regions of the immunoglobulin

variable and constant region

4

variable region of an immunoglobulin

(also called FAB- fragment antigen binding)
-the end of the immunoglobulin and the one that forms the structure that will bind to a specific antigen (fingers), variations

5

constant region of an immunoglobulin

-backbone that doesn't have as many variable combinations (only varies from one class to another)
-(also called fragment Fc region)

6

5 immunoglobulins and percentages

1. IgG - 80%
2. IgA - 15%
3. IgM - 5%
4. IgD - 0.2%
5. IgE - 0.002%

7

where is IgG usually found

epithelial tissue such as skin and conjunctiva of the eye

8

IgG is primarily responsible for

fixation of complement and opsonization

9

IgG is the principle source of ____ immunity against organisms in _____ space

humoral immunity against organisms in extravascular space

10

IgA is associated with ___ tissue

epithelial

11

what is IgA in the blood stream versus in the tissue

blood: monomer
tissue: dimeric

12

what is secretory IgA

is after dimer and secretory component are added
-it bathes epithelial tissue

13

how does secretory IgA work?

it inhibits virus particles from sticking on from epithelial surface- "it slides off like teflon paint"

14

in secretory IgA, what forms the monomers and what connects them to make a dimer

monomers are produced by lymphocytes
-dimer formed from connections from J chain

15

a unique feature of IgM is its

high molecular weight
(5 monomers)

16

IgM is especially efficient at

fixing complement (at attaching complement once it is activated to the invading organism)

17

what immunoglobulin is "first at the scene" at the site of infection

IgM

18

role of IgM is protecting _____ space

intravascular space
(blood vascular system inside the vessels)

19

IgD

nearly all IgD appears on the surface of lymphocytes (like IgM does too)- so could be related or coordinated with IgM

20

IgE is also called the

"skin sensitizing antibody"

21

IgE normally has a physiological role to

protect mucosal surfaces

22

IgE triggers release of certain agents that start inflammation response such as

-vasodilation of blood vessels
-chemotactic factors which attract macrophages

23

what is an allergy (hypersensitivity)?

an exaggerated immune response

24

type I hypersensitivity is also known as

immediate Rx, anaphylaxis

25

what occurs during initial exposure during type I hypersensitivity ?

B cells -> plasma cells, plasma cells produce type of IgE called reagin which binds to mast cells

26

what occurs during second exposure during type I hypersensitivity ?

allergen binds to IgE, destabilizing the cell membrane which bursts (if the allergen bridges two IgE molecules)
-explosive degranulization releases components from mediators

27

explosive degranulation causes the mediators to release :

-histamine
-heparin
-prostaglandins
-proteolytic enzymes

28

the mix of mediators in type I hypersensitivity causes

-smooth muscle contraction
-vasodilation (redness)
-increased vascular permeability (tissue starts to lose fluid)
-mucous secretion (causing hay fever symptoms)

29

what occurs with the mast cell in immediate hypersensitivity?

all those packets of mediators inside the mast cells blow up and released all at once

30

what occurs in systemic anaphylaxis

release of a bunch of mast cells throughout the body:
-smooth muscle contraction and bronchioles constrict
-arterioles dilate, drastically reducing blood pressure
-permeability of the vessels increases and they start losing fluid
(shock)

31

what occurs during localized anaphylaxis

localized release of mediators- often in mucous membrane, resulting in hay fever
-if in lower respiratory tract, bronchial asthma (deeper and airborne)

32

type IV hypersensitivity is also called

cell-mediated, delayed

33

what occurs during onset on type IV hypersensitivity

subset of T lymphocytes called delayed type hypersensitivity cells (TH1) recognize antigen, react, and release cytokines which can cause tissue damage

34

process during type IV hypersensitivity

-T lymphocytes recruited via cytokines
-cytokines increase capillary permeability: macrophages have exaggerated response (tissue damage)
-special T cells amplify the whole thing

35

why is it called delayed hypersensitivity

the whole process for T cells to proliferate, send out cytokines, and recruit macrophages can take a day or two

36

type IV hypersensitivity is involved in what pathologies

-autoimmune diseases
-transplant rejection
-killing cancer cells
-contact dermatitis

37

what is contact dermatitis

occurs with certain products (cosmetics, TPAs, metals)
-it is an immune reaction to something that isn't biologic

38

how can contact dermatitis illicit an immune response

small molecules called haptens when attached to a carrier (protein in the skin)- this combination is antigenic